Since a polyarylene sulfide resin, which is represented by a polyphenylene sulfide resin, has a high melting point excellent flame retardancy and chemical resistance, and good fluidity during molding, the polyarylene sulfide resin is widely used in various electronic components, mechanical parts or automobile parts as an engineering plastic for injection molding.
Recently, in the electric or electronic industry field, with maturization of products or improvement of productivity, a method of mounting a resin-based electronic component on a printed board is performed by a so-called surface mount method (hereinafter, abbreviated to an “SMT method”). In a technology of mounting an electronic component on a board by the SMT method, tin-lead eutectic solder (melting point of 184° C.) had been generally used in the past. However, recently, lead-free solder obtained by adding various types of metal to tin as a base material has been used in place of the conventional solder, due to environmental contamination.
Since the lead-free solder has a higher melting point than that of the tin-lead eutectic solder; for example, tin-silver eutectic solder has a melting point of 220° C., the temperature of a heating furnace (reflow furnace) has to be further increased at the time of surface mounting. Thus, when soldering a resin-based electronic component such as a connector, there has been a problem that the electronic component melts or deforms in the heating furnace (reflow furnace). Consequently, a high-heat-resistant resin material for a surface mount electronic component has been strongly desired.
Meanwhile, as a high-heat-resistant resin material, a resin composition obtained by melting and kneading polyarylene sulfide with aromatic polyamide has been known (for example, see Patent Document 1 and Patent Document 2). However, since the polyarylene sulfide and the aromatic polyamide generally show low compatibility, it is difficult to uniformly mix the polyarylene sulfide and the aromatic polyamide. Accordingly, a weak point of the aromatic polyamide of a low moisture absorption characteristic significantly stands out and results blistering to occur easily on the electronic component passing through the heating furnace (reflow furnace). Moreover, after the electronic component is passed through the reflow furnace, a mechanical property such as flexural strength to deteriorate. In addition to the deterioration in dispersion of polyarylene sulfide and aromatic polyamide, flame retardancy deteriorates because a large quantity of aromatic polyamide is used and thus the requirement of the electronic or electric part cannot be satisfied.
Patent Document 1: Japanese Unexamined Patent Application Publication No. H02-123159
Patent Document 2: Japanese Unexamined Patent Application Publication No. H05-5060